Tragedy as nearly 100 whales are left stranded after washing up on a New Zealand beach

Dozens of whales have washed up dead off the coast of New Zealand in the fifth stranding in less than a week.

The pod of about 90 whales washed ashore on the remote Chatham Islands, 800km east of the South Island – but more than half were found dead unable to escape.

One of the whales was in such bad shape that rangers were forced to euthanize him on arrival.

Department of Conservation manager Dave Carlton said killing the whale was ‘the most humane thing to do’, as they investigate the cause of a recent spate of strandings.

The reason whales and dolphins strand is not fully understood but theories include sickness, navigational error, geographical features, the presence of predators, and extreme weather.

The summer period is generally the time whales strand in New Zealand, but five strandings in one week is unprecedented

Dozens of whales have washed up dead off the coast of New Zealand in the fifth stranding in less than a week

One of the whales was in such bad shape that rangers were forced to euthanize him on arrival

A pod of about 90 whales washed ashore on the remote Chatham Islands, about 800km east of the South Island

‘This is always an awful decision to have to make,’ he said.

The Chatham Islands were the scene of New Zealand’s largest recorded stranding in 1918, involving 1,000 whales.

Only four days ago 145 pilot whales were found beached at Stewart Island, off the coast of the South Island.

Half were already dead, and the rest had to be euthanised due to their poor health at the time they were found.

In addition to the strandings on the South Island this week, a group of 12 pygmy killer whales also beached in New Zealand’s far north and a sperm whale and a pygmy sperm whale grounded themselves in separate incidents on the North Island.

Chatham Island was the scene of New Zealand’s largest recorded stranding in 1918, involving 1,000 whales

The reason whales and dolphins strand is not fully understood but theories include sickness, navigational error, geographical features, the presence of predators, and extreme weather

A crew prepared to bury the dead whales who were found at the coast of Chatham Island, New Zealand on Friday

Karen Stockin, a marine mammal scientist at Massey University, said while whale strandings were relatively common in New Zealand, the cluster of incidents in such a short timeframe was unusual.

She also pointed out that species such as pygmy killer whales and sperm whales did not normally beach, unlike pilot whales, which regularly wash up on New Zealand beaches in the summer months.

Ms Stockin, who is an expert consultant on strandings for the International Whaling Commission, said it added to a string of strange whale behaviour over the past year.

In addition to a rise in strandings, she said a number of species had appeared that were not normally seen in New Zealand waters, including gargantuan blue whales in the Hauraki Gulf near Auckland.

Ms Stockin said New Zealand was currently experiencing some of the warmest ocean temperatures on record and she believed it was affecting whale behaviour.

Species such as pygmy killer whales and sperm whales did not normally beach, unlike pilot whales, which regularly wash up on New Zealand beaches in the summer months

‘We’ve had an unusual week, which we haven’t got to the bottom of, and it’s fair to say it’s been an entirely unusual year,’ she told AFP.

‘I suspect a lot of that has been driven by the warmer sea surface temperatures that we’re seeing at the moment.

‘We definitely have a spike in temperatures, that’s likely affecting where the prey is moving and as a consequence we’re seeing prey moving and (whale) species following.’

New Zealand’s summer, the peak time for whales to beach, begins on Saturday and Ms Stockin said more strandings were likely.

‘We’re just going into stranding season now, this is only the beginning of it and we’re very mindful of the fact that this a very busy start,’ she said.

New Zealand is currently experiencing some of the warmest ocean temperatures on record and could be affecting whale behaviour